Investigations on pressure sensors for medical applications based on fiber Bragg gratings

The concept of fiber-Bragg grating (FBG) arrays was investigated regarding its potential to serve as a new method to fabricate cost efficient and high performance pressure sensor catheters for hollow organs. Draw tower fibers with a reduced diameter of 80 μm and a co-extrusion fabrication process were used in order to keep the catheter simple and prone to be used as one way product. The total diameter of these catheters can range literally from the fiber diameter of 80 μm up to 5 mm. Finite element based investigations on the design were followed by experimental characterization of the material parameters and the fabrication of samples. These samples were thoroughly examined regarding pressure, tension and temperature sensitivity as well as their mechanical properties like stiffness, tensile strength and geometry. As a result of these studies pressure sensor catheter designs for hollow organs in human medicine are proposed. With state of the art interrogation systems for FBG-sensor readout different kinds of measurement catheters are possible to be designed. Possible applications are motility measurements ranging from the human esophagus to the gut, containing rectum, colon and small intestine and even sphincter of Oddi which are accessible by placing the catheter via endoscopic techniques. The use in cardiac arrangements is in preparation.